1. Field of the Invention
The present invention relates to an inkjet recording head including nozzles that jet ink droplets, a pressure chamber that communicates with the nozzles and contains ink, a diaphragm that configures part of the pressure chamber, an ink pool chamber that pools ink to be supplied to the pressure chamber via an ink droplet path, and a piezoelectric element that displaces the diaphragm.
2. Description of the Related Art
Conventionally, inkjet recording devices are known where ink droplets are selectively discharged from plural nozzles of an inkjet recording head (sometimes referred to simply as “recording head” hereinafter) that reciprocally moves in a main scanning direction, and where characters and images are printed on a recording medium such as recording paper that is conveyed in a sub-scanning direction.
In such inkjet recording devices, there are piezoelectric recording heads and thermal recording heads. In the case of the piezoelectric recording head, as shown in FIGS. 14 and 15, piezoelectric elements (actuators that convert electrical energy into mechanical energy) 206 are disposed on pressure chambers 204 to which ink 200 is supplied from an ink tank via an ink pool chamber 202, and the piezoelectric elements 206 bend and deform so that the volumes of the pressure chambers 204 are reduced, whereby the ink 200 therein is pressurized and jetted as ink droplets 200A from nozzles 208 that communicate with the pressure chambers 204.
With respect to inkjet recording heads of this configuration, in recent years there has been the demand to enable high-resolution printing while keeping the inkjet recording heads inexpensive and compact. In order to meet this demand, it is necessary to dispose the nozzles in a high density, but in present recording heads, because the ink pool chamber 202 is disposed next to the nozzles 208 (i.e., between the nozzles 208 and the nozzles 208) as illustrated, there has been a limit on disposing the nozzles 208 in a high density.
Also, a drive IC that applies a voltage to predetermined piezoelectric elements is disposed in the inkjet recording head, but conventionally, as shown in FIGS. 16A and 16B, an FPC (flexible printed circuit board) 210 is mounted thereon. In other words, bumps 212 formed on the FPC 210 are bonded to metal electrode surfaces on upper surfaces of the piezoelectric elements 206 disposed on a diaphragm 214 to connect the FPC 210.
By mounting the drive IC (not shown) on the FPC 210 in such a manner, the piezoelectric elements 206 and the drive IC are electrically connected.
Also, there is a method where electrical terminals on a mounting substrate to which the drive IC is mounted are connected by wire bonding to electrode terminals disposed on an outer surface of the recording head (e.g., see Japanese Patent Application Laid-Open Publication (JP-A) No. 2-301445).
Moreover, there is a method where the drive IC is bonded and connected to the electrode terminals disposed on the outer surface of the recording head, and thereafter the FPC is bonded and connected to electrode terminals of pull-out interconnects (wiring) disposed in the recording head (e.g., see JP-A No. 9-323414).
However, any of the above-described cases, interconnects arrangement in which a pitch between each wire is minute (e.g., 10 μm pitch or less) cannot be formed. Thus, there are problems in that when the nozzle density rises, the sizes of the mounting substrate and the FPC inevitably become large, miniaturization is inhibited and costs increase. Moreover, there is the problem that when the nozzle density rises, interconnects having a desired resistance cannot be installed as desired. In other words, there is a limit on increasing the nozzle density resulting from the restriction of the interconnects density.